The 10th National People's Congress (NPC), held at the Great Hall of the People in Beijing in March last year. 2006. Photograph: Ma Zhancheng/Xinhua/AP

A fifth of the world's population will come closer to knowing the identity of their next president this week as the Chinese Communist party opens the country's most important political meeting in five years.

A "princeling" from an elite family and a cadre who made his name in poor provinces are among the favourites to succeed President Hu Jintao when his term of office expires in 2012.

At the 17th Communist party congress, which starts today, Xi Jinping, the son of a party elder, and Li Keqiang, who worked his way up from humble peasant origins, are expected to be promoted to the standing committee of the politburo, the most powerful body in China. The elevation of this pair and two or three other fifth-generation politicians will set the stage for what analysts say could prove an unusually open succession contest.

The stakes have never been higher. The general secretary of the Communist party is guaranteed the job of president, which means he will lead the fastest growing economy and an increasingly important player in global trade and diplomacy.

During the meeting of 2,017 delegates at Beijing's Great Hall of the People, Mr Hu will consolidate his power by promoting supporters from his powerbase in the Communist Youth League to the politburo and its standing committee. He is also expected to push for a reform of the party charter to include his concept of "scientific development", which seeks a more environmentally sustainable and socially harmonious model of economic growth.

Analysts do not expect major initiatives, but Mr Hu may call for greater "inner party democracy", which means more voting by communists for communists.

With 73 million members, the party increasingly resembles a giant aristocracy. "Princelings" - the children of current and former leaders - dominate the executive ranks of many of the nation's biggest firms. President Hu Jintao's daughter is married to the former head of the internet giant Sina. The son-in-law of the prime minister, Wen Jiabao, reportedly runs the country's most successful football team. The son of the former premier Li Peng controls China's biggest power generation company, while relatives of Deng Xiaoping are believed to dominate the huge Poly group.

The hereditary trend could become more pronounced if Xi Jinping, party general secretary in Shanghai, is made heir-apparent. "He would be the first princeling to take power. If that is the case, then we can truly say the Communist party has become an aristocracy," said a diplomat.

But he is not a certainty. At least four places are likely to open up on the politburo's nine-member standing committee.

Mr Hu does not have the power of past party strongmen. He must consider the interests of party factions and the wishes of his predecessor, Jiang Zemin.

"Given the present political situation in Beijing it is impossible for Hu Jintao to be dominant in making these decision," said Professor Joseph Cheng of the City University of Hong Kong. "He will make concessions and look for a balance. It not just factional, but a mix of people from rich coastal provinces, some from inland, some princelings, some bureaucratic experts, cadres from the communist youth league and the propaganda department."

Many observers believe there is no consensus. "By the time of the 18th party congress, there will be a real contest because Hu Jintao does not have the authority to pick his successor," said Li Datong, formerly an editor at a publication controlled by the Communist Youth League.

But he did not expect major reforms that would allow multi-party democracy of press freedom. "Hu is not that type of person. He was educated by the party. You cannot change his brain. He just doesn't know what freedom of the press is."

Academics say Mr Hu will have more room for manoeuvre after he wins a second term. "Usually during their first term, leaders do not show their colours fully. It is only in the second term that their ideas become fully developed and mature," said Cui Zhiyuan of Tsinghua University. "I hope that in the second term he will be more open for the media and introduce more democracy within the party."

The party has stifled debate ahead of the congress, clamping down on the domestic media, detaining dissidents and blocking internet sites.

Hardliners have long warned that increased accountability could take China down the road of Gorbachev's Soviet Union, which might lead the party to self-destruct. Professor Cui said it did not go far enough. "What is more important is mass democracy, more media openness and more power for the people's congress."